Plant growth promoting bacteria (PGPB) include rhizosphere and phyllosphere bacteria that benefit plants. PGPB in the rhizosphere, called plant growth promoting rhizobacteria (PGPR), were first described in the late 1970s. They are root-colonizing bacteria that fix nitrogen, produce phytohormones and siderophores, and inhibit pathogens through antibiosis and competition. PGPB diversity includes genera like Pseudomonas, Bacillus, Azospirillum, and Burkholderia. PGPB promote plant growth through various mechanisms and show potential for use in biocontrol, but face challenges in selection, characterization, field application, and commercialization due to natural variation and
This document discusses induced systemic resistance (ISR) in plants. It provides historical context on studies of induced resistance dating back to the late 1800s. ISR is defined as a phenomenon where treatment with certain chemicals or pathogens activates a plant's defenses throughout the plant. Key findings include:
- ISR is activated by rhizobacteria and involves jasmonic acid and ethylene signaling rather than salicylic acid signaling as in systemic acquired resistance.
- Several bacteria, fungi, chemicals, and elicitors are reported to induce ISR through different signaling pathways and defense responses.
- Further research is needed to fully understand ISR signaling and apply it effectively in fields to control plant diseases.
Avs role of plant growth promoting rhizobacteria in diseaseAMOL SHITOLE
This seminar discusses the role of plant growth promoting rhizobacteria (PGPR) in disease suppression and plant growth promotion. PGPR colonize plant roots and promote plant growth through mechanisms such as fixing atmospheric nitrogen, solubilizing mineral phosphates, producing phytohormones, antagonizing phytopathogenic microorganisms, and inducing systemic resistance in plants. The seminar outlines the definition of PGPR, common genera of PGPR including Pseudomonas and Bacillus, and the various mechanisms of action of PGPR such as nitrogen fixation, phosphate solubilization, phytohormone production, biocontrol activity, and induced systemic resistance. Experimental data is presented showing the effects of PGPR on nodulation,
This document discusses plant growth promoting rhizobacteria (PGPR). It begins by defining PGPR as beneficial bacteria that colonize plant roots and promote plant growth. It then covers the classification, characteristics, and mechanisms of action of PGPR, including direct mechanisms like nitrogen fixation, phosphate solubilization, and phytohormone production as well as indirect mechanisms like siderophore production and induced systemic resistance. The document also discusses the roles, commercialization, and importance of PGPR as biofertilizers for sustainable agriculture.
This document discusses plant growth promoting rhizobacteria (PGPR). It begins by noting the growing global population and need to increase food production. It then defines PGPR as bacteria that colonize plant roots and promote growth through various mechanisms. The document goes on to describe characteristics, mechanisms, and examples of PGPR, including biological nitrogen fixation, phosphate solubilization, phytohormone production, siderophore production, induced systemic resistance, and stress tolerance functions. A history of PGPR research is also provided, along with commercial examples.
This document provides an overview of soil-microbe-plant interactions in the rhizosphere. It discusses how plant roots release exudates that attract microbes and influence the rhizosphere environment. Microbes can benefit plants through nutrient cycling, hormone production, and pathogen inhibition. Environmental factors like temperature and moisture impact root exudates and the rhizosphere microbiome. Plant genotype and traits also shape interactions with soil microbes. The rhizosphere enhances soil quality through physical and nutrient dynamics effects. A diverse microbiome can boost plant growth, and pathogenic fungi can negatively impact plants via soil feedbacks. In conclusion, the rhizosphere is a zone where soil biology and chemistry are influenced by roots and microbes through complex
introduction to mycorrhizae and its role in P uptakeFari Rajput
This document discusses mycorrhiza and its role in phosphorus uptake by plants. It begins by defining mycorrhiza as a symbiotic relationship between plant roots and fungi, where the fungi help facilitate nutrient and water uptake in exchange for carbohydrates from the plant. There are two main types of mycorrhiza - ectomycorrhiza and endomycorrhiza. Mycorrhizal fungi take up nutrients from soil through a mycorrhizal pathway and transfer them to the plant, helping the plant access nutrients like phosphorus that are poorly mobile in soil. They do this through mechanisms like producing phosphatases and organic acids to solubilize inorganic and organic phosphorus sources, and storing
This document discusses bioinoculants, which are beneficial soil microbes used to promote plant growth. It defines bioinoculants and microbial inoculants, and explains that they are important for sustainable agriculture by reducing the need for chemical fertilizers. The document then describes the different types of relationships microbes can have with plants and lists various microbes used as inoculants, including nitrogen fixers, phosphate solubilizers, biocontrol agents, and biopesticides. It outlines the key benefits inoculants provide plants and soils, such as improving nutrition, stimulating growth, and suppressing pathogens. Finally, it notes that bioinoculants have advantages over chemical fertilizers in that they are less harmful
This document summarizes the types and development of mycorrhizal symbiosis. It discusses:
1. There are several types of mycorrhizal associations including ectomycorrhiza, ectendomycorrhiza, ericoid mycorrhiza, and VA mycorrhiza.
2. The development of the mycorrhizal symbiosis occurs through asymbiotic and symbiotic stages, beginning with spore germination and hyphal growth, followed by recognition signals between the plant and fungi leading to appresorium formation and penetration of root cells.
3. In the mature symbiotic phase, the fungi form specialized structures inside root cells like arbuscules
This document discusses induced systemic resistance (ISR) in plants. It provides historical context on studies of induced resistance dating back to the late 1800s. ISR is defined as a phenomenon where treatment with certain chemicals or pathogens activates a plant's defenses throughout the plant. Key findings include:
- ISR is activated by rhizobacteria and involves jasmonic acid and ethylene signaling rather than salicylic acid signaling as in systemic acquired resistance.
- Several bacteria, fungi, chemicals, and elicitors are reported to induce ISR through different signaling pathways and defense responses.
- Further research is needed to fully understand ISR signaling and apply it effectively in fields to control plant diseases.
Avs role of plant growth promoting rhizobacteria in diseaseAMOL SHITOLE
This seminar discusses the role of plant growth promoting rhizobacteria (PGPR) in disease suppression and plant growth promotion. PGPR colonize plant roots and promote plant growth through mechanisms such as fixing atmospheric nitrogen, solubilizing mineral phosphates, producing phytohormones, antagonizing phytopathogenic microorganisms, and inducing systemic resistance in plants. The seminar outlines the definition of PGPR, common genera of PGPR including Pseudomonas and Bacillus, and the various mechanisms of action of PGPR such as nitrogen fixation, phosphate solubilization, phytohormone production, biocontrol activity, and induced systemic resistance. Experimental data is presented showing the effects of PGPR on nodulation,
This document discusses plant growth promoting rhizobacteria (PGPR). It begins by defining PGPR as beneficial bacteria that colonize plant roots and promote plant growth. It then covers the classification, characteristics, and mechanisms of action of PGPR, including direct mechanisms like nitrogen fixation, phosphate solubilization, and phytohormone production as well as indirect mechanisms like siderophore production and induced systemic resistance. The document also discusses the roles, commercialization, and importance of PGPR as biofertilizers for sustainable agriculture.
This document discusses plant growth promoting rhizobacteria (PGPR). It begins by noting the growing global population and need to increase food production. It then defines PGPR as bacteria that colonize plant roots and promote growth through various mechanisms. The document goes on to describe characteristics, mechanisms, and examples of PGPR, including biological nitrogen fixation, phosphate solubilization, phytohormone production, siderophore production, induced systemic resistance, and stress tolerance functions. A history of PGPR research is also provided, along with commercial examples.
This document provides an overview of soil-microbe-plant interactions in the rhizosphere. It discusses how plant roots release exudates that attract microbes and influence the rhizosphere environment. Microbes can benefit plants through nutrient cycling, hormone production, and pathogen inhibition. Environmental factors like temperature and moisture impact root exudates and the rhizosphere microbiome. Plant genotype and traits also shape interactions with soil microbes. The rhizosphere enhances soil quality through physical and nutrient dynamics effects. A diverse microbiome can boost plant growth, and pathogenic fungi can negatively impact plants via soil feedbacks. In conclusion, the rhizosphere is a zone where soil biology and chemistry are influenced by roots and microbes through complex
introduction to mycorrhizae and its role in P uptakeFari Rajput
This document discusses mycorrhiza and its role in phosphorus uptake by plants. It begins by defining mycorrhiza as a symbiotic relationship between plant roots and fungi, where the fungi help facilitate nutrient and water uptake in exchange for carbohydrates from the plant. There are two main types of mycorrhiza - ectomycorrhiza and endomycorrhiza. Mycorrhizal fungi take up nutrients from soil through a mycorrhizal pathway and transfer them to the plant, helping the plant access nutrients like phosphorus that are poorly mobile in soil. They do this through mechanisms like producing phosphatases and organic acids to solubilize inorganic and organic phosphorus sources, and storing
This document discusses bioinoculants, which are beneficial soil microbes used to promote plant growth. It defines bioinoculants and microbial inoculants, and explains that they are important for sustainable agriculture by reducing the need for chemical fertilizers. The document then describes the different types of relationships microbes can have with plants and lists various microbes used as inoculants, including nitrogen fixers, phosphate solubilizers, biocontrol agents, and biopesticides. It outlines the key benefits inoculants provide plants and soils, such as improving nutrition, stimulating growth, and suppressing pathogens. Finally, it notes that bioinoculants have advantages over chemical fertilizers in that they are less harmful
This document summarizes the types and development of mycorrhizal symbiosis. It discusses:
1. There are several types of mycorrhizal associations including ectomycorrhiza, ectendomycorrhiza, ericoid mycorrhiza, and VA mycorrhiza.
2. The development of the mycorrhizal symbiosis occurs through asymbiotic and symbiotic stages, beginning with spore germination and hyphal growth, followed by recognition signals between the plant and fungi leading to appresorium formation and penetration of root cells.
3. In the mature symbiotic phase, the fungi form specialized structures inside root cells like arbuscules
This document discusses microbial transformations of sulphur, iron, and manganese in soil. It describes how various bacteria and fungi play key roles in mineralizing, immobilizing, oxidizing, and reducing these elements. Specific microbes like Thiobacillus, Desulfovibrio, and Leptothrix are involved in important processes like oxidizing elemental sulphur and iron, and reducing sulphates and ferric iron under different environmental conditions. The cycling and availability of these elements in soil largely depends on microbial activity.
Plant growth promoting bacteria (PGPB) include rhizosphere and phyllosphere bacteria that can benefit plants. PGPB are classified as either rhizoplane bacteria that colonize roots, or intracellular bacteria that exist inside root cells. PGPB promote plant growth through various mechanisms including nitrogen fixation, siderophore production, phytohormone production, phosphate solubilization, induced systemic resistance, and antagonism against pathogens. While PGPB show potential for controlling plant diseases, their commercial use faces challenges in selection and characterization, field application, and commercialization due to natural variation, formulation and delivery issues, and high costs.
Phosphate solubilizing microorganisms (PSM) such as bacteria and fungi play an important role in solubilizing insoluble phosphate in soil and making it available to plants. PSM secrete organic acids and enzymes that lower soil pH and chelate cations, converting insoluble phosphate into soluble forms that plants can absorb. While phosphorus is essential for plant growth, much of the phosphorus in soil is unavailable to plants; PSM help address phosphorus deficiency by increasing the soluble phosphorus content of soil. Further research is needed to develop methods for commercializing PSM as biofertilizers to provide a more sustainable alternative to inorganic phosphate fertilizers.
This document discusses plant-growth promoting rhizobacteria (PGPR), which are bacteria that indirectly promote plant growth through mechanisms like biological control or by directly enhancing plant growth without the presence of pathogens. PGPR colonize the rhizosphere, the soil area around plant roots, and can increase plant growth through various processes like biofertilization by fixing atmospheric nitrogen or solubilizing phosphorus, stimulating root development, degrading pollutants in the rhizosphere (rhizoremediation), or controlling plant stress by regulating the plant hormone ethylene. PGPR can also indirectly promote plant growth through biological control of pathogens using mechanisms like antibiosis, inducing systemic resistance in plants, or competing with pathogens for nutrients and space
Role of microbes in nutrient mobilization, transformation in fertilizer use e...Jayvir Solanki
This study evaluated the effect of different biofertilizer treatments on the growth and nutrient uptake of mulberry plants. Key findings:
1. Co-inoculation of mulberry plants with nitrogen fixing, phosphate solubilizing, and potash mobilizing microbes along with 100% recommended NPK fertilizer doses led to the highest growth and nutrient uptake.
2. Treatments involving 75-100% recommended NPK doses along with combinations of different biofertilizers also improved mulberry growth and soil fertility compared to the control or individual biofertilizer treatments.
3. Co-inoculation with VAM fungi or potassium mobilizing bacteria along with reduced NPK doses further enhanced mulberry
The document provides an overview of microbial ecology in soil. It discusses soil as an environment for microorganisms and describes the typical soil habitat. It explains that soils can be divided into mineral and organic types and notes the key components of vegetated soils. The document also examines soil organic matter and the roles of microorganisms like bacteria, fungi, algae, protozoa, and others in soils. It discusses various microbe-plant interactions such as those in the rhizosphere, phyllosphere, and mycorrhizal associations.
Biotechnological approches in disease managementrahul manjunath
This document discusses various biotechnological approaches for plant disease management, including tissue culture, recombinant DNA technology, and transgenic approaches. Tissue culture techniques like meristem culture can produce disease-free planting materials. Recombinant DNA technology allows generation of resistant plants by expressing genes conferring resistance to bacterial, fungal or viral diseases. Transgenic approaches discussed include pathogen-derived resistance utilizing viral coat protein or movement genes, as well as expressing plant disease resistance genes, ribosome-inactivating proteins, and genes involved in systemic acquired resistance.
Plant - Pathogen Interaction and Disease DevelopmentKK CHANDEL
Plant diseases are the result of infection by any living organisms that adversely affect the growth, development, physiological functioning and productivity of a plant, manifesting outwardly as visible symptoms.
This document provides an overview of plant growth promoting rhizobacteria (PGPR). It discusses that PGPR are a group of soil bacteria that colonize plant roots and enhance plant growth directly or indirectly. Direct mechanisms include biological nitrogen fixation, phosphate solubilization, phytohormone production, siderophore production, and antibiotic production. Indirect mechanisms include inducing systemic resistance in plants, production of lytic enzymes, and stress tolerance effects. The document reviews the specific mechanisms of several important PGPR functions and commercially available PGPR products.
phyllosphere is a dynamic rapidly changing area surrounding the germinating seed. there are two categories of microbes one is positively enhancing and negatively reducing the plant yield
Agricultural microbiology deals with plant-associated microbes and soil fertility. Microbes play an important role in biogeochemical cycles like carbon, nitrogen, and sulfur cycles. They decompose organic matter and release nutrients. Biofertilizers like nitrogen-fixing bacteria and mycorrhizal fungi supplement chemical fertilizers. Biopesticides using bacteria like B. thuringiensis, fungi, and viruses control agricultural pests. Microbes also produce phosphorus-solubilizing enzymes and control nematodes, benefiting agricultural productivity.
This document discusses the degradation of herbicides in soil. It begins with definitions of degradation and decomposition, explaining that degradation is a broader term that includes decomposition. The document then discusses how herbicides reach the soil and the various fates they may undergo, including herbicidal activity, physical removal processes like adsorption, vaporization, leaching, run-off, and codistillation, and decomposition processes like biotic and abiotic decomposition. It focuses on explaining adsorption and microbial decomposition in more depth. Key factors that affect these degradation processes like soil properties, climate conditions, and the chemical properties of the herbicide are also summarized.
The document discusses Plant Growth Promoting Rhizobacteria (PGPR), including their importance and role in agriculture. It defines PGPR, classifies them into two types, and describes their mechanisms of action such as nitrogen fixation, phosphate solubilization, siderophore production, and phytohormone production. The document outlines PGPR's role as phytostimulators, in abiotic stress tolerance, as biofertilizers, and biopesticides. It discusses the commercialization and future research of PGPR to potentially replace chemical fertilizers and pesticides.
Importance of microorganisms in nutrient managementsanthiya kvs
The document discusses the important role of soil microorganisms in nutrient management and cycling. It explains that microbes are actively involved in decomposing organic matter, producing humus, and increasing the availability of nutrients like phosphorus. Certain microbes also support plant growth by producing vitamins, hormones, and stimulating natural defenses against pathogens. Microorganisms are key players in soil carbon, nitrogen, phosphorus, and sulfur cycles through processes like nitrogen fixation, nitrification, denitrification, and mineralization. The document also discusses different types of biofertilizers containing beneficial microbes.
Mechanism of disease control by endophytesPooja Bhatt
The document discusses alternative methods for pest management to address problems with chemical pesticides such as development of resistance and environmental contamination. It suggests that biological control using endophytic microorganisms is a promising alternative as endophytes have antagonistic properties against plant pathogens. Endophytes can inhibit pathogens through direct mechanisms such as hyperparasitism, competition, antibiosis, and lytic enzyme production or indirect induction of host plant resistance. Case studies provide examples of endophytes inhibiting fungal plant pathogens through siderophore production, parasitic growth, and antibiotic compounds.
This document summarizes induced plant resistance against pathogens. It discusses the historical background of induced resistance being first observed over 100 years ago. It describes different types of induced resistance including systemic acquired resistance (SAR) and induced systemic resistance (ISR). SAR is mediated by salicylic acid and involves pathogenesis-related proteins, while ISR is mediated by jasmonic acid and ethylene. Biological agents like PGPR bacteria and plant extracts can also induce resistance. Signal transduction pathways underlying these responses are triggered upon pathogen recognition. While induced resistance offers opportunities for crop protection, practical applications are currently limited to some plants.
Rohit Jadhav presented on microbe-plant interactions. Key points include:
- Cyanobacteria and rhizobia have symbiotic relationships with plants, fixing nitrogen.
- Microbes in the rhizosphere and rhizoplane interact with plant roots, satisfying nutritional needs for both.
- Rhizosphere microbes can positively impact plants by nutrient solubilization or negatively through immobilization.
- Legumes form root nodules with rhizobia like Rhizobium spp. and Bradyrhizobium spp. to fix atmospheric nitrogen.
- Some non-legumes interact with nitrogen-fixing cyanobacteria and Frankia bacteria inside root nodules.
-
The document discusses biofertilizers as an alternative to chemical fertilizers. It defines biofertilizers as microorganisms that enrich soil fertility. Some key types discussed include nitrogen-fixing biofertilizers like Rhizobium and Azospirillum, and phosphate-solubilizing microorganisms. Application methods are also summarized, including seed treatment, set treatment, seedling treatment, and soil application. The benefits of biofertilizers are increasing crop yields, replacing chemical fertilizers, stimulating plant growth, and restoring soil fertility in a cost-effective and eco-friendly manner.
Plant microbe interaction by dr. ashwin chekeAshwin Cheke
PLANT MICROBE – INTERACTIONS AND THEIR MUTUAL BENEFITS IN ENHANCING SOIL HEALTH AND AGRICULTURAL PRODUCTION ,
IT ALSO INCREASE CROP PRODUCTIVITY AND IMPROVE SOIL HEALTH
This document provides an overview of plant growth promoting rhizobacteria (PGPR). It begins with an introduction to PGPR and their potential as an alternative to pesticides in agriculture. It then covers the classification of PGPR into extracellular and intracellular types. The main mechanisms by which PGPR promote plant growth are discussed, including nitrogen fixation, phosphate solubilization, siderophore production, phytohormone production, and biocontrol activities. The roles of PGPR in agriculture as biofertilizers, biostimulants, and biopesticides are outlined. Future research directions are identified, such as developing multi-strain bacterial consortia. The conclusion emphasizes the multiple beneficial activities of PGPR for plant growth and
This document discusses microbial transformations of sulphur, iron, and manganese in soil. It describes how various bacteria and fungi play key roles in mineralizing, immobilizing, oxidizing, and reducing these elements. Specific microbes like Thiobacillus, Desulfovibrio, and Leptothrix are involved in important processes like oxidizing elemental sulphur and iron, and reducing sulphates and ferric iron under different environmental conditions. The cycling and availability of these elements in soil largely depends on microbial activity.
Plant growth promoting bacteria (PGPB) include rhizosphere and phyllosphere bacteria that can benefit plants. PGPB are classified as either rhizoplane bacteria that colonize roots, or intracellular bacteria that exist inside root cells. PGPB promote plant growth through various mechanisms including nitrogen fixation, siderophore production, phytohormone production, phosphate solubilization, induced systemic resistance, and antagonism against pathogens. While PGPB show potential for controlling plant diseases, their commercial use faces challenges in selection and characterization, field application, and commercialization due to natural variation, formulation and delivery issues, and high costs.
Phosphate solubilizing microorganisms (PSM) such as bacteria and fungi play an important role in solubilizing insoluble phosphate in soil and making it available to plants. PSM secrete organic acids and enzymes that lower soil pH and chelate cations, converting insoluble phosphate into soluble forms that plants can absorb. While phosphorus is essential for plant growth, much of the phosphorus in soil is unavailable to plants; PSM help address phosphorus deficiency by increasing the soluble phosphorus content of soil. Further research is needed to develop methods for commercializing PSM as biofertilizers to provide a more sustainable alternative to inorganic phosphate fertilizers.
This document discusses plant-growth promoting rhizobacteria (PGPR), which are bacteria that indirectly promote plant growth through mechanisms like biological control or by directly enhancing plant growth without the presence of pathogens. PGPR colonize the rhizosphere, the soil area around plant roots, and can increase plant growth through various processes like biofertilization by fixing atmospheric nitrogen or solubilizing phosphorus, stimulating root development, degrading pollutants in the rhizosphere (rhizoremediation), or controlling plant stress by regulating the plant hormone ethylene. PGPR can also indirectly promote plant growth through biological control of pathogens using mechanisms like antibiosis, inducing systemic resistance in plants, or competing with pathogens for nutrients and space
Role of microbes in nutrient mobilization, transformation in fertilizer use e...Jayvir Solanki
This study evaluated the effect of different biofertilizer treatments on the growth and nutrient uptake of mulberry plants. Key findings:
1. Co-inoculation of mulberry plants with nitrogen fixing, phosphate solubilizing, and potash mobilizing microbes along with 100% recommended NPK fertilizer doses led to the highest growth and nutrient uptake.
2. Treatments involving 75-100% recommended NPK doses along with combinations of different biofertilizers also improved mulberry growth and soil fertility compared to the control or individual biofertilizer treatments.
3. Co-inoculation with VAM fungi or potassium mobilizing bacteria along with reduced NPK doses further enhanced mulberry
The document provides an overview of microbial ecology in soil. It discusses soil as an environment for microorganisms and describes the typical soil habitat. It explains that soils can be divided into mineral and organic types and notes the key components of vegetated soils. The document also examines soil organic matter and the roles of microorganisms like bacteria, fungi, algae, protozoa, and others in soils. It discusses various microbe-plant interactions such as those in the rhizosphere, phyllosphere, and mycorrhizal associations.
Biotechnological approches in disease managementrahul manjunath
This document discusses various biotechnological approaches for plant disease management, including tissue culture, recombinant DNA technology, and transgenic approaches. Tissue culture techniques like meristem culture can produce disease-free planting materials. Recombinant DNA technology allows generation of resistant plants by expressing genes conferring resistance to bacterial, fungal or viral diseases. Transgenic approaches discussed include pathogen-derived resistance utilizing viral coat protein or movement genes, as well as expressing plant disease resistance genes, ribosome-inactivating proteins, and genes involved in systemic acquired resistance.
Plant - Pathogen Interaction and Disease DevelopmentKK CHANDEL
Plant diseases are the result of infection by any living organisms that adversely affect the growth, development, physiological functioning and productivity of a plant, manifesting outwardly as visible symptoms.
This document provides an overview of plant growth promoting rhizobacteria (PGPR). It discusses that PGPR are a group of soil bacteria that colonize plant roots and enhance plant growth directly or indirectly. Direct mechanisms include biological nitrogen fixation, phosphate solubilization, phytohormone production, siderophore production, and antibiotic production. Indirect mechanisms include inducing systemic resistance in plants, production of lytic enzymes, and stress tolerance effects. The document reviews the specific mechanisms of several important PGPR functions and commercially available PGPR products.
phyllosphere is a dynamic rapidly changing area surrounding the germinating seed. there are two categories of microbes one is positively enhancing and negatively reducing the plant yield
Agricultural microbiology deals with plant-associated microbes and soil fertility. Microbes play an important role in biogeochemical cycles like carbon, nitrogen, and sulfur cycles. They decompose organic matter and release nutrients. Biofertilizers like nitrogen-fixing bacteria and mycorrhizal fungi supplement chemical fertilizers. Biopesticides using bacteria like B. thuringiensis, fungi, and viruses control agricultural pests. Microbes also produce phosphorus-solubilizing enzymes and control nematodes, benefiting agricultural productivity.
This document discusses the degradation of herbicides in soil. It begins with definitions of degradation and decomposition, explaining that degradation is a broader term that includes decomposition. The document then discusses how herbicides reach the soil and the various fates they may undergo, including herbicidal activity, physical removal processes like adsorption, vaporization, leaching, run-off, and codistillation, and decomposition processes like biotic and abiotic decomposition. It focuses on explaining adsorption and microbial decomposition in more depth. Key factors that affect these degradation processes like soil properties, climate conditions, and the chemical properties of the herbicide are also summarized.
The document discusses Plant Growth Promoting Rhizobacteria (PGPR), including their importance and role in agriculture. It defines PGPR, classifies them into two types, and describes their mechanisms of action such as nitrogen fixation, phosphate solubilization, siderophore production, and phytohormone production. The document outlines PGPR's role as phytostimulators, in abiotic stress tolerance, as biofertilizers, and biopesticides. It discusses the commercialization and future research of PGPR to potentially replace chemical fertilizers and pesticides.
Importance of microorganisms in nutrient managementsanthiya kvs
The document discusses the important role of soil microorganisms in nutrient management and cycling. It explains that microbes are actively involved in decomposing organic matter, producing humus, and increasing the availability of nutrients like phosphorus. Certain microbes also support plant growth by producing vitamins, hormones, and stimulating natural defenses against pathogens. Microorganisms are key players in soil carbon, nitrogen, phosphorus, and sulfur cycles through processes like nitrogen fixation, nitrification, denitrification, and mineralization. The document also discusses different types of biofertilizers containing beneficial microbes.
Mechanism of disease control by endophytesPooja Bhatt
The document discusses alternative methods for pest management to address problems with chemical pesticides such as development of resistance and environmental contamination. It suggests that biological control using endophytic microorganisms is a promising alternative as endophytes have antagonistic properties against plant pathogens. Endophytes can inhibit pathogens through direct mechanisms such as hyperparasitism, competition, antibiosis, and lytic enzyme production or indirect induction of host plant resistance. Case studies provide examples of endophytes inhibiting fungal plant pathogens through siderophore production, parasitic growth, and antibiotic compounds.
This document summarizes induced plant resistance against pathogens. It discusses the historical background of induced resistance being first observed over 100 years ago. It describes different types of induced resistance including systemic acquired resistance (SAR) and induced systemic resistance (ISR). SAR is mediated by salicylic acid and involves pathogenesis-related proteins, while ISR is mediated by jasmonic acid and ethylene. Biological agents like PGPR bacteria and plant extracts can also induce resistance. Signal transduction pathways underlying these responses are triggered upon pathogen recognition. While induced resistance offers opportunities for crop protection, practical applications are currently limited to some plants.
Rohit Jadhav presented on microbe-plant interactions. Key points include:
- Cyanobacteria and rhizobia have symbiotic relationships with plants, fixing nitrogen.
- Microbes in the rhizosphere and rhizoplane interact with plant roots, satisfying nutritional needs for both.
- Rhizosphere microbes can positively impact plants by nutrient solubilization or negatively through immobilization.
- Legumes form root nodules with rhizobia like Rhizobium spp. and Bradyrhizobium spp. to fix atmospheric nitrogen.
- Some non-legumes interact with nitrogen-fixing cyanobacteria and Frankia bacteria inside root nodules.
-
The document discusses biofertilizers as an alternative to chemical fertilizers. It defines biofertilizers as microorganisms that enrich soil fertility. Some key types discussed include nitrogen-fixing biofertilizers like Rhizobium and Azospirillum, and phosphate-solubilizing microorganisms. Application methods are also summarized, including seed treatment, set treatment, seedling treatment, and soil application. The benefits of biofertilizers are increasing crop yields, replacing chemical fertilizers, stimulating plant growth, and restoring soil fertility in a cost-effective and eco-friendly manner.
Plant microbe interaction by dr. ashwin chekeAshwin Cheke
PLANT MICROBE – INTERACTIONS AND THEIR MUTUAL BENEFITS IN ENHANCING SOIL HEALTH AND AGRICULTURAL PRODUCTION ,
IT ALSO INCREASE CROP PRODUCTIVITY AND IMPROVE SOIL HEALTH
This document provides an overview of plant growth promoting rhizobacteria (PGPR). It begins with an introduction to PGPR and their potential as an alternative to pesticides in agriculture. It then covers the classification of PGPR into extracellular and intracellular types. The main mechanisms by which PGPR promote plant growth are discussed, including nitrogen fixation, phosphate solubilization, siderophore production, phytohormone production, and biocontrol activities. The roles of PGPR in agriculture as biofertilizers, biostimulants, and biopesticides are outlined. Future research directions are identified, such as developing multi-strain bacterial consortia. The conclusion emphasizes the multiple beneficial activities of PGPR for plant growth and
A creative way to learn about the bacteria Rhizobium with a touch of Bollywood. For young, science minds. This was a part of my college curriculum as I am studying Microbiology Hons.
PGPR can promote sustainable agriculture in 3 ways:
1. They fix atmospheric nitrogen into a form plants can use through nitrogen-fixing bacteria like Rhizobium.
2. They solubilize insoluble phosphorus and other nutrients like potassium through organic acid production, making them available to plants.
3. They produce plant hormones like auxins and cytokinins that stimulate plant growth and help plants withstand stresses.
This document discusses the use of microbes to help crops manage abiotic stress. It introduces beneficial microbes like plant growth promoting rhizobacteria (PGPR) and describes their classification. These microbes can fix nitrogen, solubilize phosphorus and potassium to make them available to plants. They also produce phytohormones and organic acids that help plants tolerate stresses like drought and salinity. The document discusses various nitrogen fixing, phosphate solubilizing and potassium solubilizing microbes and their mechanisms of action. It also covers mycorrhizal fungi that help plants uptake nutrients and water.
The document discusses plant growth promoting rhizobacteria (PGPR) and their mechanisms and functions in promoting plant growth. It describes how PGPR can directly promote plant growth through mechanisms like nitrogen fixation, phosphate solubilization, siderophore production and phytohormone production. PGPR also indirectly promote growth by inhibiting pathogens through producing antibiotics, lytic enzymes and inducing systemic resistance in plants. Future research areas discussed include developing PGPR consortium, improving stress tolerance and making PGPR products more cost effective and environmentally friendly.
Microbial endophytes are microorganisms that live within plant tissues without causing disease or harm. They have been isolated from many plant species worldwide and show diversity across environments. Endophytes are isolated from surface-sterilized plant tissues and identified based on genetic sequencing. Bacterial endophytes provide benefits like nitrogen fixation, plant growth promotion, biocontrol of pathogens, and abiotic stress resistance. Fungal endophytes also produce secondary metabolites and biocontrol pathogens. Future work aims to develop endophytes as biofertilizers and biopesticides through improved isolation techniques and delivery methods.
Pseudomonas is a genus of bacteria that can act as both plant pathogens and biocontrol agents. As pathogens, certain Pseudomonas species like P. syringae can infect a wide range of plants, causing spots, blights or dieback. However, some Pseudomonas like P. fluorescens act as biocontrol agents against plant pathogens by producing antibiotics, siderophores, and inducing systemic resistance in plants. Pseudomonas are also effective biopesticides due to traits such as rapid growth, root colonization, and production of bioactive metabolites against fungal and bacterial pathogens.
This document discusses plant growth-promoting microbes (PGPM) which are soil microorganisms that can positively influence plant growth. PGPM are divided into two main groups - plant growth-promoting rhizobacteria (PGPR) and plant growth-promoting fungi (PGPF). PGPR and PGPF help plants grow through mechanisms like nitrogen fixation, phosphate solubilization, siderophore production, phytohormone synthesis, and protecting plants from pathogens. They play important roles in agricultural sustainability by improving soil fertility, supplying nutrients, suppressing diseases, and assisting in environmental remediation.
This document provides an introduction to phytobacteriology. It defines phytobacteriology as the subdiscipline of plant pathology that deals with prokaryotic plant pathogens and their interactions. It discusses the basic and applied aspects of studying phytobacteriology, including morphology, physiology, taxonomy, genetics, serology, host-pathogen interactions and pathogenesis. It also explains why the study of phytobacteriology has expanded to include beneficial bacterial interactions with plants as well as ice nucleation active bacteria which can cause frost damage. The document differentiates prokaryotes from eukaryotes and provides details on characterizing and classifying bacteria and archaea. It concludes by listing some economically important pathogenic prokaryotes and the
The document discusses the role of siderophores in plant pathogen interactions. It provides background on siderophores, their importance in microbial metabolism, types of siderophores produced by different organisms, and their mechanism of iron acquisition. It summarizes several case studies that demonstrate how siderophore-producing bacteria can be used for biocontrol of plant pathogens through competition for iron and activation of plant defense responses. Siderophores are shown to elicit plant defenses, modulate signaling pathways, and promote bacterial growth during infection.
Biocontrol of pathogens using siderophores, antibiotics, enzymes FOR STUDENTS...thirupathiSathya
biocontrol of pathogens by using siderophores, enzymes, antibiotics.
siderophores: iron seequestering molecules
bacteria producing siderophores more tightly binded than fungi producing siderophores
Antibiotics: some organism producing antibiotic is sensitive to other organism eg, fungi producing antibiotic penicillin is sensitive to bacteria
Enzymes: organism producing enzymes like glucanase, chitinase are able to degrade the fungal cell walls ..
by using these theme recombinant method is employed to degrade specific organism in a particular aspects.
1) Bacterial biofilms are resistant to antibiotics and contribute to chronic infections. Exposure to antibiotics can enhance biofilm formation in some bacteria and induce antibiotic resistance.
2) Alternative approaches to control biofilm infections include using natural products, enzymes to degrade the biofilm matrix, inhibiting quorum sensing, bioactive agents, nanoparticles, and photodynamic therapy.
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it describes the bony anatomy including the femoral head , acetabulum, labrum . also discusses the capsule , ligaments . muscle that act on the hip joint and the range of motion are outlined. factors affecting hip joint stability and weight transmission through the joint are summarized.
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centuries, evolving its structure over time and space. In the present era, these changes have
accelerated due to factors such as agriculture and urbanization. Information regarding land use and
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3. INTRODUCTION
• PGPB includes Rhizoplane and Phylloplane bacteria.
Rhizoplane Bacteria:
• “Plant Growth Promoting Rhizobacteria”(PGPR).
• Term PGPR was first used by Joseph W. Kloepper
and Schroth in the late 1970s.
• PGPR are root colonizing (rhizosphere) bacteria
benificial to plants.
• Rhizosphere is the region around roots having high
microbial activity.
4. • Term Rhizosphere was
coined by German
agronomist Hiltner in
1904.
• Rhizoplane
The external surface of
roots together with closely
adhering soil particles and
debris.
5. DIVERSITY AMONG PGPRS
Diazotrophic PGPR
Nitrogen Fixation is one of the most beneficial
processes performed by rhizobacteria.
Rhizobacteria converts gaseous nitrogen (N2) to
ammonia (NH3) making it available to the host plant.
Nitrogenase enzyme is involved in nitrogen fixation
and requires anaerobic conditions.
Ex- Azospirillum, Bradyrhizobium, Rhizobium,
Serratia, Enterobacter , Burkholderia spp.
6. Bacillus
95% of Gram +ve soil bacilli belong to the genus
Bacillus.
The remaining 5% are confirmed to be Arthrobacter
and Frankia.
Members form endospores to survive under
adverse conditions.
Pseudomonas
Pseudomonas is the most abundant gram –ve genus
in rhizosphere.
The ecological diversity of this genus is enormous.
7. • Pseudomonas strains show high
versatility in their metabolic activity.
• Antibiotics, siderophores, HCN are
the metabolites released by these
strains.
8. Taxonomy of PGPB
Earlier bacterial taxonomy relied on phenotypic
traits like cell and colony morphologies.
Taxonomy revolutionized with the discovery of PCR
technique in 1983.
The gene sequences of 16S subunit of rRNA are
used to compare similarities among strains.
Nowadays characteristics of strains are studied
using FAME technique, Protein estimation by SDSPAGE technique and MLEE.
9. Classification of PGPR
On the basis of
1. Plant part they occupy
Intracellular (iPGPR, symbiotics)
Exist inside root cells.
Forms root nodules.
Ex- Rhizobium
Extracellular (ePGPR, free living
Exist in rhizosphere,on
rhizoplane, in intercellular
spaces of root cortex.
10.
11.
12. Siderophore Production
• Siderophores are high-affinity iron chelating
compounds secreted by microorganisms.
• Siderophores chelate ferric ion with high
affinity, allowing its solubilization and extraction
from most mineral or organic complexes.
• Bacterial siderophores classified into four main
classes carboxylate, hydroxamates, phenol
catecholates and pyoverdines.
14. Microbial Antagonism
Achieved through bacteriocins, antibiotics
hydrolytic enzymes,HCN production, SAR, ISR.
Antibiotics
PGPR produces
antibiotics and act as
antagonistic.
Biocontrol based on
Pathogen
antibiosis secretion of
molecules that kill
target pathogen
Antibiosis
ISR
Competition
15. Sr. Antibiotic
No
Source
Action against
1.
Pyrrolnitrin
P. Fluorescens
BL915 strain
Prevent the damage
of Rhizoctonia solani during
damping-off of cotton plants
2.
DAPG
Pseudomonas
spp.
Membrane damage
to Pythium spp.
3.
Phenazine
Pseudomonas
spp.
F. oxysporum,
Gaeumannomyces graminis
4.
Polymyxin,
circulin and
colistin
Bacillus spp.
Pathogenic fungi
5.
Zwittermicin A B. cereus UW85 Bio-control of alfalfa damping
strain
off
16. Production of Phytohormones
• Phytohormone production by PGPR was first
reported in 1940.
• Auxin and Ethylene are more commonly produced
hormone, Cytokinin is less common.
• Auxin promotes lateral root formation, cell division,
apical dominance etc.
• Among PGPR species, Azospirillum is one of the best
studied IAA producers (Dobbelaere et al., 1999)
17. ROOTS WITHOUT PGPR
ROOTS WITH PGPR
• Production of Gibberellins by PGPR is rare,
• However two strains have been reported, Bacillus
pumilis and Bacillus licheniformis.
19. • Strawberry fruits were harvested and transported
to the laboratory.
• Dipped in a suspension of B. cinerea conidia and
allowed to dry for 1 h.
• Then inoculated with bacterial suspensions.
• Control fruits dipped in conidia, dried and dipped in
nutrient broth diluted with sterile distilled water,
• Fruits were incubated for 4 days at 25°C, and then
observation was recorded.
Donmez et al., 2011
21. Result:
• No significant differences between CD-8, MFD4, MFD-18, MFDÜ-1 and control
• Highest percentage of gray mold infection (79.2%)
was observed in the control and
• Lowest (20.8%) was in MFD-45, followed by MFD81 (25.0%) and T26 (37.5%).
Conclusion:
PGPB were effective in biocontrol of Botrytis
cinerea on strawberry fruit.
22. Fixation of Atmospheric N2
• There are two types of biological fixation:
symbiotic and non-symbiotic.
• The first is the most important mechanism by which
most atmospheric N is fixed.
• It is limited to legume plant species and various trees
and shrubs that form actinorrhizal roots
with Frankia.
• Non-symbiotic N-fixing rhizospheric bacteria belongs
to genera including
Azoarcus, Azospirillum, and Pseudomonas
23. Most studied symbiotic bacteria
are Rhizobium, Bradyrhizobium, Sinorhizobium and
Mesorhizobium
24. Induced Systemic Resistance
• PGPR interact with plant in a restricted area but
response is extended to whole plant.
• Salicylic acid, which plays a protective role in
acquired systemic resistance .
• While acquired systemic resistance is induced upon
pathogen infection, induced systemic resistance can
be stimulated by other agents, such as PGPB
inoculants.
• Plants inoculated with the biocontrol PGPB, P.
putida and Serratia marcescens were protected
against the cucumber pathogen P. syringae pv.
lachrymans.
Bashan &Bashan., (2005)
26. Role of siderophore in induction of SAR
• E. chrysanthemi produces two
siderophores
Achromobactin ( iron limiting
condition)
Chrysobactin (severe iron
deficiency)
The role of CB in induction of
SAR has been studied in
Arabidopsis- Erwinia
chrysanthemi system.
27. Cont.
Fig: PR1 gene expression and SA production in Arabidopsis leaves
following CB treatment (Dellagi et al., 2009).
28. Production of Enzymes
• Hydrolytic enzymes produced by some biocontrol PGPB
lyse specifically fungal cell walls, and thereby prevent
phytopathogens from proliferating .
• Ex. Pseudomonas stutzeri produces chitinase that lyse
cell wall of Fusarium solani.
• Another strategy is the hydrolysis of fungal products
harmful to the plant.
• Ex.Cladosporium werneckii and B. cepacia can hydrolyze
fusaric acid that causes severe damage to plants.
(Hillel, 2005)
32. Competition and Displacement of
Pathogens
• Competition for nutrients and suitable niches
among pathogens and is another mechanism of
biocontrol of some plant diseases.
• Ex- high inoculum level of Pseudomonas syringae
protected pears against Botrytis cinerea and
Penicillium expansum .
• Bacteria capable of multiplying on the leaf surface
to form a large population can compete successfully
with pathogens for these sites and often reduce
disease.
33. List of PGPRs
PGPR
Disease promoting
traits
References
Pseudomonas
fluorescens
IAA, HCN
Jeon et al. (2003)
Pseudomonas
fluorescens
IAA, Siderophore,
Antifungal activity
Dey et al. (2004)
Bacillus subtilis
Antifungal activity
Cazorla et al. (2007)
Bradyrhizobium spp.
IAA,Siderophore, HCN
Wani et al. (2007a)
Pseudomonas, Bacillus
, IAA and Siderophores
Wani et al. (2007e)
Azospirillum
amazonense
IAA, Nitrogenase activity
Elisete et al. (2008)
Rhizobium
leguminosarum
IAA, Siderophores, HCN,
Exopolysaccharides
Ahemad and Khan
(2009a)
34. PHYLLOPLANE BACTERIA
• Defined as populations that can
survive and multiply on the surface of
plants.
• Also called as epiphytic bacteria.
• survive in trichomes
base, substomatal
chambers, hydathodes, and
especially, in between the depressions
along the junctions of adjacent
epithelial cells.
• They utilize similar mechanism for
controlling of pathogens like
antibiosis, siderophore production etc.
35. Location of the epiphytotic PGPB in tomato
P. macerans
P. macerans
B. pumilus
B. pumilus
control
control
36. Bacterial spot and early blight biocontrol by
epiphytotic bacteria in tomato plants
Filho et al., 2010
38. Conclusion
(I) Paenibacillus macerans and Bacillus pumilus
epiphytic bacteria and benzalkonium chloride reduce
Xanthomonas vesicatoria and Alternaria solani disease
severity in tomato plants.
(II) Epiphytic bacteria are able to inhibit the growth of
tested phytopathogens, and efficiently
colonize the phylloplane of tomato plants.
40. Challenges in Selection and
Characterization of PGPB
• Lack of proper selection and screening procedure
thus most promising organisms aren’t identified.
• Effective strategies for initial selection and
screening of PGPB isolates are required.
• Selection of PGPB with the potential to control soilborne pathogens
• Selection based on traits known to be associated
with PGPB such as root colonization, ACC
deaminase activity, antibiotic and siderophore
production.
41. Con…
Natural variation
Prediction how an organism will respond
when placed in the field (compared to the
controlled environment of a laboratory.
lack of consistency and many variation in
results that are obtained in field trials
PGPB bacteria will not live forever in a
soil/leaves, there is need to re-inoculate
seeds to bring back populations.
42. Challenges in Field Application
of PGPB
CHALLENGE
• Lack
of
consistent
performance in the field
due to heterogeneity of
abiotic and biotic factors.
KNOWLEDGE
MANAGEMENT
REMEDY
• Knowledge of factors
optimal
concentration, timing and
placement
of
inoculant, and of soil and
crop
management
strategies
• concept of managing the
rhizosphere/phyllosphere
by manipulation of the
host plant, substrates for
PGPB,
or
through
agronomic practices.
44. •
•
•
•
Challenges in Commercialization of PGPB
Maintaining quality, stability, and efficacy of
the product.
Factors like shelf life, compatibility
considered while formulation development.
Non-target effects on other organisms
including toxigenicity, allergenicity,
pathogenicity.
Capitalization costs and potential markets
must be considered in the decision to
commercialize.
45. CONCLUSION
• PGPB has dual role as plant growth
promotion and as bioagent.
• They control the plant pathogen in
direct as well as indirect way.
• PGPB is available in nature but their
screening is not easy.
• It is included in IDM strategy for
controlling several plant pathogens.